In some call processing systems, it may be desirable to detect the occurrence of events, such as three-way calling events, as may be invoked by a remote calling party and/or may be attempted to be hidden from a call processing system. For example, in prison call processing systems, prisoners are often forbidden from calling some parties, i.e., judges, victims, witnesses, and the like. Accordingly, some prisons have adopted call processing systems that use a list of allowed and/or disallowed telephone numbers for individual prisoners and/or all prisoners collectively. When an inmate attempts to call a forbidden number or a number which is not an allowed number, the prison call processing system does not set up a call. To avoid the call processing system blocking such calls, some inmates have attempted to call an outside party and then use the outside party to establish a three-way call with the forbidden phone number. In that case, since an outside line is already established, the challenge becomes enabling the call processing system to recognize three-way calls from outside lines and disconnect the call in response thereto.
An example prison call processing system monitors signals on a telephone line for a burst of sub-300 hertz energy that is typically associated with a hook flash (i.e., depressing the hook switch on a telephone). Hook flashes are the usual method whereby users signal to the telephone company's central office to set up a three way call. Upon detecting a hook flash, the prison call processing system disconnects the call to prevent unauthorized contact with forbidden parties.
Noisy dual-tone multi frequency (DTMF) touch-tone keypads, especially dirty keypads, can produce a click when making connection during actuation, thereby creating a sound with sub-300 hertz energy. This can create a problem when an inmate makes a collect call to a party. According to conventional methods, upon receiving the collect request, the called party enters a number by depressing a DTMF key to accept the call. However, the prison call processing system may mistake this accept signal for a three-way event and disconnect the call before the conversation begins. It is a challenge for call processing system designers to program the systems to distinguish between hook flashes and other sounds, such as dirty keypads. In addition to dirty keypads, other phenomena result in low accuracy for event-detection algorithms. For example, noises caused by the telephone system itself switching the caller from a recorded message to a connected conversation may fool the system into detecting a false event.
Currently, it is difficult for a technician or administrator to debug or set-up a system because the data that is analyzed by the system is often not saved. Further, current systems are embodied in hardware, often in specialized boards that do not offer ways to view the operation in real time. In fact, users are usually limited, at most, to inspecting the debug registers of the board's processor. Thus, debugging or setting up a system is often time consuming and frustrating because of a lack of available and convenient information for the technician. Further, owners of the system (and potential customers) may not be able to satisfy themselves of proper operation because of the same lack of information.